Tokuyama Y, Tokuyama H
Department of Nuclear Medicine, Faculty of Medicine, Kanazawa University, Ishikawa-ken, Japan.
Cell Immunol. 1996 Jun 15;170(2):230-4. doi: 10.1006/cimm.1996.0156.
The role of retinoids was analyzed in directing isotype switching to IgA and IgG1 (IgE) by LPS-stimulated murine mu(+)B-cells in the presence of two Th2-type cytokines, IL-4 and IL-5. All trans retinoic acid (RA) enhanced the production of IgA at high concentrations (10-100 nM) in the presence of IL-5. Addition of IL-4 to the system modulated the IgA response in a dose-dependent manner. Namely, IL-4 inhibited the response at concentrations higher than 250 u/ml, but showed slight enhancement at lower concentrations (130 u/ml). IL-4 alone, which is considered to be an IgE isotype-switch inducer, strongly enhanced the IgG1 and IgE responses. Addition of IL-5 to the system showed a synergistic effect which could be attenuated by addition of low concentrations of RA (about 1 nM). Thus, the presence of switch modulators such as IL-4 and IL-5, their concentration ratios, and concentrations of retinoids are crucial factors in initiating and directing isotype switching to IgA and IgG1 (IgE).
在两种Th2型细胞因子IL-4和IL-5存在的情况下，分析了类视黄醇在引导LPS刺激的小鼠μ(+)B细胞向IgA和IgG1（IgE）进行同种型转换中的作用。在IL-5存在的情况下，全反式维甲酸（RA）在高浓度（10-100 nM）时增强了IgA的产生。向该系统中添加IL-4以剂量依赖的方式调节IgA反应。也就是说，IL-4在浓度高于250 u/ml时抑制反应，但在较低浓度（130 u/ml）时显示出轻微增强。单独的IL-4，被认为是一种IgE同种型转换诱导剂，强烈增强了IgG1和IgE反应。向该系统中添加IL-5显示出协同作用，而添加低浓度的RA（约1 nM）可减弱这种协同作用。因此，诸如IL-4和IL-5等转换调节因子的存在、它们的浓度比以及类视黄醇的浓度是启动和引导向IgA和IgG1（IgE）进行同种型转换的关键因素。
